No, pop3 isn't involved here at all. All communication between mail servers is done via smtp and Reaper is using a webmail account. pop3 and imap are client (your machine) to server protocols.
'sok though, e-mail is so retardedly complex for something that should be so retardedly simple someone needs a solid beating.
Since the mail queue processing here is nearly instantaneous - a minute during a bad hour - and we talk directly to the receiving servers it's not much of an issue on our end.
Basically, hotmail/live sees a flood of messages from our ip, says "o hai we're getting a lot of messages right now, we'll send it in a bit 'kay?" and sends a delayed message notification back to us. If it's really bad I'll get an e-mail from <!-- e --><a href="mailto
ostmaster@hotmail.com">postmaster@hotmail.com</a><!-- e --> saying that the delay is going to be extra long (several hours).
If we had our own rdns-matching domain name to send e-mails to/from, we'd get placed in a separate queue from elliquiy and also get even more special treatment.
Honestly though? Whining about seven minutes?